The present invention concerns a communications system consisting of a communications apparatus and of a test apparatus for testing of the communications apparatus, as well as a method for testing of a communications apparatus.
Telephone communications apparatuses can be built up with permanently connected telephones or with mobile telephones or a combination of the two.
The basic constituent parts of a mobile telephone communications apparatus are mobile telephones and base apparatuses having transmission stations. Thus, the mobile telephones which are in operation stay in connection with a respective one of the transmission stations via radio signals. Between the transmission stations themselves or also permanent line connections can be provided. Such a communications apparatus normally also has interfaces to change for example permanent communications apparatuses with which telephones are connected via fixed lines.
Dialing a call number from a mobile telephone will create a connection from the mobile telephone to the nearest lying transmission station, which for its part establishes the connection to the desired subscriber either via other transmission stations or via an interface to another communications system.
In order to make sure that a mobile telephone can always make a connection to a transmission station, the transmission stations must be so arranged that their catchment areas cover an area completely. It must further be ensured that a call is not interrupted if one of the participating mobile telephones moves out of the catchment area of a transmission station (also known as a cell). For these cases, handover procedures are provided in order to hand a call connection from the transmission station of a first cell to a mobile telephone to the transmission station of a second cell, if a mobile telephone moves from the first to the second cell.
Furthermore, the mobility of the user causes requests to come through that, unlike in a permanent network, in which a call can simply be directed to another permanent user network address, in a mobile telephone network, the place of a called mobile telephone must be established (paging) before initiation of a call and that, depending on a location of the mobile telephone in relation to a transmission station and depending on the geography (city, countryside), otherwise strong signals are weakened.
Moreover, customer service facilities, like for example, conference switching, voicemail services, data transmission, etc., must be provided in a mobile telephone communications system, which must be partially able to be activated by the respective telephones.
A mobile telephone communications apparatus is therefore a complex system, which is usually established and operated by an interaction of hardware and software components.
Standardized guidelines for a mobile communications system are laid down for example in the Global System for Mobile Communications (GSM). GSM specifies the features of a network, like, for example, the communications protocol between mobile telephones and transmission stations, the handover of a call between transmission stations, the requirements of a mobile telephone of a customer of a network operator in the network of another operator, speech and data services, connections to available networks, to ISDN-services and a range of other user service provisions.
The complexity of a mobile telephone communications system demands the possibility of specific testing of individual components or of the complete system. Extensive tests are carried out for localizing software and hardware faults appearing in the system during operation, prior to the release of the system and prior to the release of a further development of the system. In the prior art, a range of different test strategies have been developed, in order to carry out the testing of communications systems effectively. One of these test methods is the so-called "black box testing" in which the operation of the system in reaction to a defined interference in the system is analysed, without making any reference to the internal construction of the system.
DE 3 211 967 describes a switching arrangement for an apparatus with which different operating and test sequences are effected in a telephone exchange system or in an apparatus connected thereto, and an unusual pattern is displayed, whereby these processes are executed by a control calculation unit belonging to the system on the basis of information which is selectively transmitted to it by means of a corresponding operation of a key assigned to an input unit and this execution results from access to storage units which is thereby effected, in which storage units the necessary execution functions are contained as corresponding command sequences, especially for a unit used for traffic simulation in telephone networks and provided with the corresponding subscriber simulations. Functions typical for the system, like for example line occupation, dialing, calling and speech can be simulated by means of the subscriber simulations. According to the provisions of a predetermined test program of a program-controlled test unit, specific tone pitches generated by a transmitter are applied to the subscriber simulations. Monitoring takes place by evaluating the transmitted audible tones, the call current and, if necessary, dialing pulses.
The subscriber simulations of DE 32 119 67 have the disadvantage that no features corresponding to a real telephone can be incorporated into the test processes. Thus, a communications system cannot be tested with the inclusion of features of various telephones, for example of a variety of manufacturers.
When testing a communications network with mobile telephones, the features of the mobile telephones can have an important effect on the test conditions.